In recent years, as hoses for use with piping for a kitchen or a wash stand, a flush tank of a toilet, or other piping for feeding cold or hot water, flexible hoses are used, which include: an inner layer formed of a rubber or a thermoplastic elastomer; and a reinforcing layer thereon, which is formed by weaving, for example, a stainless steel wire, nylon, and/or a polyester fiber. Such hoses are provided with joint parts fastened by caulking at opposite ends thereof, and are referred to as “hose-type flexible expansion joints”, which are used for various piping works.
However, since a space for piping work is relatively small and a length of a hose used is short, the hose-type flexible expansion joint is often forcedly bent during piping work, and/or external forces are often applied thereto from surrounding members in contact therewith.
Therefore, the hose may suffer from a kink, where a bent portion of the hose is made to be flat. When a kink occurs, a flow path of water may be blocked and a flow rate of water may be reduced. In an extreme case, water may be inhibited from flowing through the hose.
Particularly, in a case where the inner layer of the hose is formed of, for example, a polybutene resin or a cross-linking polyethylene resin in order to protect the hose-type flexible expansion joint from running water (city water) containing chlorine, the hose has a high hardness and therefore is not easily bent. Such hoses tend to suffer from kinks, and therefore, improved hoses have been desired.